Maxtrac to CDM1250 swap question?

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a1emt
Posts: 105
Joined: Thu Jan 02, 2003 7:44 am

Maxtrac to CDM1250 swap question?

Post by a1emt »

I am needing to replace some existing VHF Maxtrac radios for narrowbanding. Looking for an easy "swap" using existing mounting brackets and wiring. Can a CDM1250 slide into the existing bracket and plug into power and 16-pin accessory wiring? Would there be a better choice (m1225, PM400)?

Thanks in advance,

Jim
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SteveC0625
Posts: 467
Joined: Sat Jan 01, 2011 9:46 am
What radios do you own?: CDM's, CP's, CM's, and more

Re: Maxtrac to CDM1250 swap question?

Post by SteveC0625 »

a1emt wrote:I am needing to replace some existing VHF Maxtrac radios for narrowbanding. Looking for an easy "swap" using existing mounting brackets and wiring. Can a CDM1250 slide into the existing bracket and plug into power and 16-pin accessory wiring? Would there be a better choice (m1225, PM400)?

Thanks in advance,

Jim
The CDM's are narrower so you'd have to swap out the mounting brackets, I believe. Double check on your end - CDM brackets are a hair under 6.75" wide.

Unless you are jumping up to a higher power unit, the power cables should be OK, but now is the time to inspect them closely looking for rubs, cracks, etc. If any doubts, replace it.

The 16 pin accessory connectors will work, but if the MaxTracs have one or two small jumpers, they have to be removed. One enables the internal speaker and is not needed in the CDM's. The other bypasses the emergency switch if the logic board is programmed with Pin 9 as external emergency switch input. That one is not needed either.l

Center the 16 pin plugs in the 20 pin connector so that two pins are visible on each side.

You will want to verify the accessory connector wires and functions with the programming of the CDM's. It's pretty much the same but there are some differences. All the pinouts are readily available over on batlabs.

FWIW, the M1225 and the PM400 would present exactly the same issues as the CDM's: narrower, don't the speaker jumper, etc.
User avatar
SteveC0625
Posts: 467
Joined: Sat Jan 01, 2011 9:46 am
What radios do you own?: CDM's, CP's, CM's, and more

Re: Maxtrac to CDM1250 swap question?

Post by SteveC0625 »

One other small thing. If your existing installs use Pin 10 for ignition sense, it's the same on the CDM's, but make they are programmed for On/Off & Ignition sense.
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a1emt
Posts: 105
Joined: Thu Jan 02, 2003 7:44 am

Re: Maxtrac to CDM1250 swap question?

Post by a1emt »

Thanks for the detailed response Steve. This will be of great help as I move forward! At least I can reuse the wiring, if not the trunnion bracket!

Jim
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